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Progress Report supported by Boeing Higher Education Program- Graduate Student Project -

Evaluation of Supersonic Wind Tunnel Testing using a Magnetic Suspension and Balance System

– Wing Model�

Tohoku UniversityIssei Tanaka , Hiroki Senda , Kei Komatsubara

Background %SuperSonic Transport%

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Possibility of wind tunnel by magnetic support

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Sting

M∞ >1

Wind tunnel with no influence of support interference is promising

❒ Implementation Issues for SST

➣ Reduction of Sonic Boom

Near-field pressure measurement/evaluation is required

� Conventional wind tunnel tests using mechanical support

Support Interference between support mechanism & wake flow

Obstruction of high precision measurement

for near-field pressure waveform occurs

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Background �Magnetic Suspension and Balance System�

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Feature❒ No support interference❒ Force evaluation by magnetic force

( Balance function )

Especially�with 0.1 m – MSBS

❒ Magnetic suspension at high dynamic pressure

❒ Magnetic suspension at supersonic range

by 6-axis control using wing models is not performed

Controlling roll axis & adjustment of test conditions are required

Support a model by interaction between a permanent magnet and magnetic field

S

N S

N

!

"

#7#3

N

S S

N

S N

S S

N NModel

0.1m-MSBS [ Coil ]Generate magnetic field in the test section

[ Position Sensor ]Measure position & attitudewith high speed & accuracy

[Model ]Permanent magnet is inside

[ Computer ]Control magnetic forcefrom measurement data

Current status

Establishment of supersonic wind tunnel technique with wing model with no support interference

Objective

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1. Construction of test environment at supersonic range by 6-axis control

2. Wind Tunnel Test

Target1 Verification of 6-axis control technique

Target2 Wing model

Establishment of supersonic wind tunnel test technique with wing model by 0.1 m - MSBS

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Control by magnetic force

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ü Magnetic field is formed in three dimensions

ü Rolling moment is generated by arranging small magnets around each 45 deg.

!"#$$⁄− !#( − !#) − !#* + !#, )⁄(!#. − !#/ − !#0 + !#1) )

Combination of roll axis control current

Combination of model magnets

34567 ( ⁄3#8 + 3#9) 2

3;<4= ⁄(3#> + 3#? + 3#@ + 3#A) 4

3C<DE ( ⁄3#F + 3#G + 3#H + 3#I) 4

3J<EKL ⁄(3#F + 3#G − 3#H − 3#I) 4

3M6N ⁄(3#> + 3#? − 3#@ − 3#A) 4

Coil current’s Combinations

Control & evaluate each axis by coil current’s combinations

Position & attitude angle measurement

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!"#$%& = −)*+,#. + )*01#.

2+ 34

5"#$%& = −6789#: ;67<=

#: ;6789#> ;67<=

#>

?

@"#$%& = −6789#A ;67<=

#A ;6789#B ;67<=

#B

?

C"#$%& = −6789#A ;67<=

#A D6789#B D67<=

#B

?EF

G"#$%& = −6789#: ;67<=

#: D6789#> D67<=

#>

?EF

Edge of model surface & black marker are detected,Position & attitude angle are measured.

H − IJKLAdd two black makers for controlling roll angle

M"#$%& = −ℎ*+,#O + ℎ*01#O + ℎ*+,#P + ℎ*01#P

43

− 6789#: ;67<=#: ;6789#> ;67<=

#>

?R

J, T, U, V, 4 − IJKL

Sensor arrangement layout

Change of M count depends on modell radius,The smaller model diameter, the more difficult it is to measure

W , C

X ,G

Y ,M

J, T, U �3 mmV, 4 �3 deg.H �5 deg.

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Experiment System & Condition

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Suction type supersonic wind tunnel with collection tunnel

Designed Mach number 1.7Test section diameter 85 mmFlow Time About 4 sec

�Collection tunnel reduces initial total pressure→ It can reduce Starting load

�Adjust the upstream butterfly valve’s opening→ It can adjust total pressure during steady stete

Butterfly

valve

(Upstream)

Butterfly valve

(Downstream)

Second throat

Nozzle

Honeycom

b

Mesh

Vacuum

tank

MSBS

&

Collection tunnel

Airflow

&

Condition1

Condition2

Reynolds number 1.4�106

Reynolds number 7.3�105

Length φ10�80 mmMaterial SUS, Resin

Wind Tunnel Testing -Target1-

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Control 6-axis 5-axisx [mm] -0.07 -0.17y [mm] -0.21 -0.33z [mm] -0.27 -0.33θ [deg] 1.38 1.79ψ [deg] -1.41 1.56! [deg] 0.7

Mach 1.7 3.0 s

Maximum displacement during air flow

6-axis control technique which performs wind tunnel tests by suppressing rotation of the model was verified

� 5-axis vs. 6-axis controlDifference of displacement → Due to the difference in model weight & inertia moment

� Control current of ! axis was Max 3.12ACoils #1 ~ #8 can output 15A steady → Sufficiently controllable

� Displacement of ! axis was Max 0.7 deg→ Sufficient magnet force support accuracy was confirmed

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Wind Tunnel Testing -Target2-

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x [mm] -0.19y [mm] 0.03z [mm] 0.07θ [deg] -0.23ψ [deg] -0.28! [deg] 1.18

Test using 3/4 span length model of AGARD-B could be performed up to Re 7.3�105 .

�Compared to Target1, displacement other than ! axis was small because of the small Reynolds number test.

�Due to this test added wings, rotation of ! axis increased.

Specifications refer to AGARD-B

�Span Length 33 mm (3/4 span length)

�Full length φ11�93.5

�Material Resin,brass

Maximum displacement during air flow

Wind Tunnel Testing -Target2-

� 10Model3

Floating model

Test Scene

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Conclusions

• Axisymmetric model6-axis control technique which performs wind tunnel tests

by suppressing rotation of the model was verified.• Wing model

Test using a 3/4 span length model of AGARD-B could be performed up to Re 7.3�105 .

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Future work� Supersonic wind tunnel test with AGARD-B model

� Near-field pressure measurement

Establishment of supersonic wind tunnel test technique with wing model by 0.1 m - MSBS

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